GRAND CANYON NATIONAL PARK, Ariz.— Conservation groups have sent a letter (see PDF) urging federal regulators to suspend operations at a uranium mine near the Grand Canyon, where millions of gallons of uranium-laced groundwater threaten people and wildlife. Records from the U.S. Geological Survey show that the contaminated groundwater — 80 times the limit set to protect public health and the environment — have inundated the Pinenut uranium mine immediately north of Grand Canyon National Park. It is unknown whether deep aquifers and nearby springs in the national park are also being polluted.

“The big question now is whether contaminated water has moved from the mine into deep aquifers that feed Grand Canyon springs,” said Grand Canyon Trust Program Director Roger Clark. “Once polluted, remediation of the aquifers would be impossible. If agencies can’t ensure against that pollution — which they can’t — then mining should not occur.”

Records show that when the Pinenut mine was reopened in 2009, the mine operator estimated that 2.85 million gallons of water had accumulated in the mine and that it was in direct contact with high-grade uranium for nearly two decades, but water storage capacity outside the mine was limited and the water could not be pumped out to prevent seepage into the watershed. In addition, 1,500 tons of uranium ore were stored at the site when the mine was temporarily closed in 1989. That ore was subsequently eroded by wind and water, allowing the uranium to dissolve into accumulated water.

Water from the mineshaft exceeds federal water-quality standards of the Safe Drinking Water Act. In the repository pond dissolved uranium levels are 2,400 micrograms per liter — 80 times the upper limit allowed under federal law. This highly contaminated wastewater threatens migratory birds and other wildlife that are attracted to the mine’s open-air evaporative pond.

“We have raised concerns about groundwater contamination repeatedly and the agencies who are supposed to be protecting public health, public lands and public waters have ignored those concerns,” said Sandy Bahr, chapter director for Sierra Club’s Grand Canyon Chapter. “It’s unconscionable that regulatory agencies permit such risks to Grand Canyon’s wildlife and groundwater without requiring the needed protections to prevent permanent harm.”

Records also show ongoing groundwater flow into the mine. Even after a mine closes, federal rules allow mine operators to dispose of low-grade ore and waste rock in the mineshaft before sealing it. There are no mechanisms in federal or state plans to ensure that polluted water does not move from the mine into deep aquifers after the mine is closed.

“Water is continually flowing into these mines, increasing the risk to deep aquifers and springs and opening the door to an environmental disaster,” said Katie Davis, public lands campaigner for the Center for Biological Diversity. “The BLM has ignored this problem for too long. We need our public officials to act now and respond to this crisis.”

In August 2013 Grand Canyon Trust, Sierra Club and the Center for Biological Diversity petitioned the Bureau of Land Management under the federal Administrative Procedures Act to require a new mining plan of operations from mine operators in light of the millions of gallons of polluted water inundating the mine. The Bureau has not responded to that petition. The groups sent a third letter to the agency on Tuesday urging action on the petition.

Tuesday’s letter requests that BLM take action, based on their authority under the Federal Land Policy Management Act, by ordering an immediate suspension of the Pinenut operations to protect health, safety and the environment.

Background In 2012 the Obama administration issued a “mineral withdrawal” prohibiting new mining claims and the development of claims lacking valid existing rights across 1 million acres of public land surrounding Grand Canyon National Park. Despite public protests and legal challenges from local American Indian tribes and conservation groups, federal agencies have allowed three uranium mines predating the withdrawal to resume operations. One of those, the Pinenut mine, was originally approved in 1986, but the mine owners closed the mine in 1989 because of low market demand for uranium. The BLM allowed the mine to reopen in 2009 after a request from Pinenut.

In 2010 water samples summarized by the USGS showed that 15 springs and five wells contained dissolved uranium concentrations in excess of the Environmental Protection Agency’s standards for safe drinking water. The USGS report concluded that these contaminated sites “are related to mining processes.”

In 2013 Grand Canyon Trust, Sierra Club and the Center for Biological Diversity submitted a rulemaking petition to the BLM under the Administrative Procedures Act to update its operating plan to incorporate new information regarding uranium-mining risks to groundwater. The agency has not responded to the petition.

In 2013 the National Park Service said that the “regional aquifer groundwater wells at the Canyon, Pinenut, and Hermit mines as well as the sumps at the base of Pigeon and Hermit mines have all exhibited dissolved uranium concentrations in excess of drinking water standards (30 micrograms per liter), with sump concentrations at Hermit Mine exceeding 36,000 micrograms per liter.”

The mission of the Grand Canyon Trust is to protect and restore the Colorado Plateau — its spectacular landscapes, flowing rivers, clean air, diversity of plants and animals, and areas of beauty and solitude.

The Sierra Club is America’s largest and most influential grassroots environmental organization, with more than 2.4 million members and supporters nationwide, including 35,000 in Arizona as part of the Grand Canyon Chapter. Sierra Club’s mission is to explore, enjoy, and protect the wild places of the earth; to practice and promote the responsible use of earth’s ecosystems and resources; and to educate and enlist humanity to protect and restore the quality of the natural and human environment. For more information, visit http://arizona.sierraclub.org/

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 775,000 members and online activists dedicated to the protection of endangered species and wild places. http://www.biologicaldiversity.org